at91sam9g20-cu ATMEL Corporation, at91sam9g20-cu Datasheet - Page 406

• Manufacturer Part Number: at91sam9g20-cu
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

30.7.4
Name:
Access Type:
• TD: Transmit Data
Data to be transmitted by the SPI Interface is stored in this register. Information to be transmitted must be written to the
transmit data register in a right-justified format.
• PCS: Peripheral Chip Select
This field is only used if Variable Peripheral Select is active (PS = 1).
If PCSDEC = 0:
If PCSDEC = 1:
• LASTXFER: Last Transfer
0 = No effect.
1 = The current NPCS will be deasserted after the character written in TD has been transferred. When CSAAT is set, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
This field is only used if Variable Peripheral Select is active (PS = 1).
406
PCS = xxx0
PCS = xx01
PCS = x011
PCS = 0111
PCS = 1111
(x = don’t care)
NPCS[3:0] output signals = PCS
31
23
15
–
–
7
AT91SAM9G20 Preliminary
SPI Transmit Data Register
30
22
14
SPI_TDR
Write-only
–
–
6
NPCS[3:0] = 1110
NPCS[3:0] = 1101
NPCS[3:0] = 0111
forbidden (no peripheral is selected)
NPCS[3:0] = 1011
29
21
13
–
–
5
28
20
12
–
–
4
TD
TD
27
19
11
–
3
26
18
10
–
2
PCS
25
17
–
9
1
6384B–ATARM–15-Dec-08
LASTXFER
24
16
8
0